A prober is known as an apparatus for measuring an electrical characteristic of a semiconductor device, e.g., a power device or a memory formed on a semiconductor wafer (hereinafter, simply referred to as “wafer”) W that is a substrate.
The prober includes a disk-shaped probe card 111 having a plurality of cantilever-type probe needles 110 shown in FIG. 12. As shown in FIG. 13, the prober makes each probe needle 110 of the probe card 111 contact with an electrode pad 120, which serves as a measuring electrode, arranged corresponding to each electrode of a semiconductor device, and allows a test current to flow from each of the probe needles 110 to the electrode pads 120, thereby measuring an electrical characteristic of the semiconductor device (see, e.g., Patent Document 1). At this time, a wafer W is mounted on a stage that is movable by, e.g., a linear motor, and by moving the stage, each probe needle 110 of the probe card 111 is positioned to correspond to each electrode pad 120.
In a conventional wafer, since an integration degree of a semiconductor device is not so high, it is possible to arrange each electrode pad 120 having a relatively large flat plate shape to correspond to each electrode of the semiconductor device. However, recently, an integration degree of a semiconductor device has become high and the number of electrodes of the semiconductor device has increased, so that it is difficult to arrange each electrode pad 120 to correspond to each electrode.
In response, instead of the flat plate-shaped electrode pads 120, relatively small hemispherical solder bumps 130 shown in FIG. 14A have been arranged in a high density on a wafer W to correspond to electrodes of the semiconductor device (see FIG. 14B); e.g., about 10,000 or more bumps per device are being arranged. However, the cantilever-type probe needles 110 have a limit to be miniaturized and their high density arrangement is difficult. Therefore, it is difficult to arrange a large number of probe needles 110 at the probe card in a high density.
Accordingly, in the probe card 111, instead of the cantilever-type probe needles 110, there are provided columnar probe electrodes 141 protruding downward and each having at a leading end thereof a protuberant engagement part 140. In this case, a wafer W is made to approach the probe card 111 (FIG. 15A), the probe electrodes 141 are brought into contact with the solder bumps 130 (FIG. 15B), and the engagement parts 140 are pushed into the solder bumps 130 to engage the probe electrodes 141 with the solder bumps 130 (FIG. 15C). By doing so, the probe electrodes 141 and the solder bumps 130 maintain contact with each other.
Patent Document 1: Japanese Patent Application Publication No. H7-297242
However, when the probe electrodes 141 are brought into contact with the solder bumps 130, a reaction force due to a fine misalignment between the probe electrodes 141 and the solder bumps 130 may be applied to the probe card 111, or the probe card 111 may be thermally expanded by the heat generated by current flow while the electrical characteristic of the semiconductor device is measured. Then, the probe card 111 may move along a surface of the wafer W (see a black arrow in FIG. 15C).
At this time, a moving force is applied to the solder bumps 130 due to the movement of the probe card 111 (see a white arrow in FIG. 15C) while the linear motor is operated to keep the stage from moving. Since the linear motor generates torque to offset the moving force, load occurs in the linear motor. For example, a moving force of 30 kgf or more may be generated with respect to one device, so that when the linear motor generates torque to offset the moving force, the linear motor may be overloaded to be damaged in some cases.